import java.util.*;
class EX2_5 {
	public static void main(String args[]) {
		int start = 0,end,middle;
		int a[] = {12,45,67,89,123,-45,67,20175126};
		int N = a.length;
		for(int i=0; i<N;i++){
			for(int j = i+1; j <N;j++) {
				if(a[j] < a[i]) {
					int t = a[j];
					a[j] = a[i];
					a[i] = t;
				}
			}
		}
	Scanner scanner = new Scanner(System.in);
	System.out.println("输入整数，程序判断该整数是否在数组中：");
	int number = scanner.nextInt();
	int count = 0 ;
	end = N;
	middle=(start+end)/2;
	while(number!=a[middle]){
		if(number>a[middle])
			start = middle;
		else if(number<a[middle])
			end = middle;
		middle = (start+end)/2;
		count++;
		if(count>N/2)
			break;
	}
	if(count>N/2)
		System.out.printf("%d不在数组中.\n",number);
	else
		System.out.printf("%d在数组中.\n",number);
	}
}
